Present and future of high-temperature superconductor quantum-based voltage standards. - Alexander M. Klushin; Jérôme Lesueur; Marian Kampik; Felix Raso; Andrea Sosso; Sergey K. Khorshev; Nicolas Bergeal; François Couëdo; Cheryl Feuillet-Palma; Paolo Durandetto; Michal Grzenik; Krzysztof Kubiczek; et al. (IEEE Instrum. Meas. Mag., 2020)